Evidence of the Zn vacancy acting as the dominant acceptor in n-type ZnO -: art. no. 205502

We have used positron annihilation spectroscopy to determine the nature and the concentrations of the open volume defects in as-grown and electron irradiated (E-el=2 MeV, fluence 6x10(17) cm(-2)) ZnO samples. The Zn vacancies are identified at concentrations of [V-Zn]similar or equal to2x10(15) cm(-3) in the as-grown material and [V-Zn]similar or equal to2x10(16) cm(-3) in the irradiated ZnO. These concentrations are in very good agreement with the total acceptor density determined by temperature dependent Hall experiments. Thus, the Zn vacancies are dominant acceptors in both as-grown and irradiated ZnO.